Bones, weight painting and very weird deformations
Enter edit mode for the armature and select the bone you want to be the parent. Go back to object mode.

Select the object to be the child, then shift select the armature.

Press CtrlP and select Bone. You can't choose which bone here, it will be set to the bone that was selected when the armature was in edit mode.



You can verify the settings under the Object Properties - Relations



You can choose to set these properties manually but you may need to re-position the object afterwards.